Biological Invasions最新文献

Cycads hold important economic and conservation value. Some species are extensively used in landscaping, while others are endangered and legally protected. The Australian cycad-attacking weevil, Siraton internatus, is notably destructive, occasionally causing infestations and invasions across various countries. This study simulated habitat suitability for S. internatus to assess its potential invasion and the impact of climate change. Habitat suitability was evaluated under current climate and four climate change scenarios over two time frames (2050 and 2090). Furthermore, we investigated the threat posed by S. internatus to cycad reserves, using Taiwanese reserves as a representative case. Our MaxEnt predictions demonstrated high accuracy, meeting multiple evaluation criteria. We explored the potential distribution of S. internatus within Australia and internationally, identifying suitable habitats in Africa, the Americas, Asia, and Europe. The case study highlighted the low habitat suitability within the two Taiwanese cycad reserves, which is projected to decrease to unsuitable levels under future climate change scenarios for this weevil species. Moreover, our results revealed that suitable habitat for S. internatus is projected to contract globally under all climate scenarios and time periods, but expansion in Chile and the southern Himalaya (e.g., Nepal). This study provides valuable insights into cycad conservation and pest invasion risks. The results support both global and local efforts to manage the invasion threats from this destructive Australian cycad-attacking weevil species. It also accentuates the urgency for continuous biosecurity inspections and prevention of exporting mature cycad caudexes from Australia.

Biodiversity commonly contributes to ecosystem functioning and provides ecosystem services. Biochar application is frequently used to remediate soils contaminated with heavy metals. As many invasive plant species can quickly form huge amounts of biomass, they are potentially useful for producing biochar for remediating contaminated soils. However, it remains untested whether invasive species richness contributes to biochar-mediated soil remediation. We applied single biochar made from each of six invasive plant species and biochar mixtures (i.e., mixtures of biochar derived from 2, 3, and 6 invasive plant species) to soils contaminated with cadmium (Cd), with no biochar application as the control. We then grew native plant communities on these soils. Compared to the control, biochar application significantly decreased Cd bioavailability (− 34% averaged across the three richness treatments) in the soils, and this effect increased with increasing invasive species richness involved in the biochar mixtures (from − 22 to − 38%). Biochar application significantly increased both the concentration (+ 126%) and pool size (+ 59%) of Cd in roots of the native plant community, although it significantly decreased its biomass (− 25%). Thus, invasive species diversity can contribute to biochar-mediated remediation of soils contaminated with Cd. Our findings indicate a novel biodiversity-mediated ecosystem service, i.e., the use of multiple invasive plant species for the production of biochar. As harvesting of invasive species for biochar production may also contribute to their management, this might mitigate the two ecological problems at once.

Monitoring population parameters of invasive species gains importance as these species continue to expand all over the world. Monitoring of invasive mammalian mesopredators is, however, complicated due to their nocturnal and secretive behaviour. In the European Union, the most common invasive mesopredator is the raccoon dog (Nyctereutes procyonoides), which causes concerns for native species, such as endangered waterfowl that may be subject to nest predation. We studied the density of mesopredators in southern Finland with wildlife cameras, using methodology of distance sampling. We deployed in total of 175 camera traps around 11 (spring 2020) and 16 (spring 2021) lakes or wetlands. We inferred densities for raccoon dogs, and for native mesopredators the red fox (Vulpes vulpes) and the European badger (Meles meles) for comparison. Raccoon dogs were found to have higher overall as well as site-specific densities (about 3.7 ind./km²) than badgers (1.2 ind./km²) and red foxes (0.6 ind./km²). The raccoon dogs also were present at every study wetland, while badgers were not found at all sites. The red fox showed more diurnal activity compared to raccoon dogs and badgers. Camera trap distance sampling enabled us to provide a density estimates on a rather small spatial and temporal scale for species of similar size and movement speed. It could therefore prove valuable as a long-term monitoring option, as climate trends are likely to further enable raccoon dog expansion. Currently this invasive species appears to be the most common mesopredator around wetlands in the southern boreal zone of southern Finland.

Diadumene lineata is one of the most widely distributed sea anemones in the world. It is usually found in estuaries, gulfs and bays over a broad range of substrates such as oysters, rocks, seaweeds and docks. In this study, we report the presence of D. lineata in a rocky outcrop located on an open ocean sandy beach on the Argentinian coast. We analysed the occurrence, abundance and size of anemones on two biogenic substrates: the native mussel Brachidonthes rodriguezii and the invasive oyster Magallana gigas. The probability of occurrence of the anemone was significantly higher in oysters compared to mussels, and since M. gigas is scattered and sparsely distributed among the mussels, we suggest that oysters may provide a more suitable substrate for the growth and reproduction of the anemone. Larger mussels and oysters supported a greater number of anemones, indicating a non-random distribution that favoured larger individuals within the patches. A marginally significant relationship was observed between the size of anemones and oysters, suggesting that larger oysters offer better growth conditions for this species. We propose that the presence of D. lineata on the open ocean sandy beach is associated with the previous record of M. gigas in the area, suggesting a potential invasional meltdown process between these exotic species.

Alligator weed (Alternanthera philoxeroides) is a highly invasive species that has successfully established in numerous tropical and subtropical regions worldwide. Previous literature suggests that alligator weed was introduced to China in the 1930s as fodder for military horses by Japanese, while its presence in Japan only became apparent in the 1990s. Consequently, the introduction and genetic relationship between alligator weed populations in China and Japan remain uncertain, and the native source population is still unidentified. This study aimed to characterize the genetic diversity and structure of populations within the introduced range of China and Japan, as well as the native range of Argentina, using amplified fragment length polymorphism (AFLP) markers. Nine primer pairs were employed, resulting in a total of 573 distinct amplified bands for the China and Japan populations. However, none of these bands displayed polymorphism, indicating a uniform genetic background across all sampled populations in China and Japan. In contrast, the Argentine populations yielded 251 identifiable amplified bands using four well-performing primer pairs, of which 209 (80.69%) were found to be polymorphic. Genetic relationship and population structure analyses based on AFLP data revealed that the population from Jujuy, Argentina, exhibited the closest genetic affinity to the invasive populations in China and Japan, as indicated by Nei’s genetic identity value of 0.9281. Additionally, using methylation-sensitive amplified polymorphism (MSAP), we identified 258 epigenetic variation sites using five primer pairs in the Chinese and Japanese populations. Principal coordinate analysis (PCoA) based on the MSAP data revealed a geographic epigenetic structure within the alligator weed populations of China and Japan, with DNA methylation variation patterns exhibiting correlation with geographic distribution, thus implying their potential involvement in environmental adaptation. This research enhances our understanding of the invasion mechanisms of alligator weed and provides valuable insights into the roles of epigenetic factors in its successful spread.

Across many ecosystems in North America and Europe, native freshwater bivalves (Order Unionida) are threatened by fouling and competition for food by the invasive zebra mussel Dreissena polymorpha. In light of climate change, knowledge on the influence of water temperature on these competitive effects is important, yet poorly understood. This study examines the physiological impact of the interaction between D. polymorpha and the native European unionid Anodonta cygnea over a 28 day—period in response to water temperatures of 12, 19, and 25 °C by comparing their glycogen, glucose, lipid and protein concentrations. The laboratory experiment comprised three treatments: (1) fouling of A. cygnea by D. polymorpha, (2) both species present but not fouling; and (3) a control in which A. cygnea and D. polymorpha were placed separately. Increased water temperatures caused physiological stress in D. polymorpha as evident from reduced glycogen, glucose, lipid and protein concentrations. Dreissena polymorpha benefited from fouling of unionids, as individuals that fouled A. cygnea tended to have increased glycogen, glucose, lipid and protein concentrations. Competitive effects of D. polymorpha over the unionid bivalve species, however, were not intensified by elevated temperatures. Glochidia release, lower infestation intensity, and physiological stress of Dreissena at higher temperatures were likely confounding factors. The results of this study suggest that understanding the physiological consequences of species interactions at changing temperatures can be an important tool to assess future climate change impacts on freshwater bivalves and aquatic community structures.

Invasions of nonnative species have multiple implications, including modification of biogeochemical cycles, inhibition of natural regeneration of native species, and loss of ecosystem biodiversity and productivity. Japanese honeysuckle (Lonicera japonica Thunb.) is a vigorous invader of the southern forestlands of the United States (U.S.). Our objectives were to document changes in the distribution of Japanese honeysuckle since the turn of the century, identify climatic variables correlated with its successful invasion, and project its potential future distribution under climate change. To accomplish this, we analyzed the most recent U.S. Forest Service field measurements of Japanese honeysuckle in the southern U.S. Our analysis indicated that the number of sampled plots invaded by Japanese honeysuckle from 2009 to 2017 increased by approximately 53% compared to plots sampled from 2000 to 2008, and the mean percent coverage of Japanese honeysuckle in sampled plots increased significantly. Results of boosted regression tree analysis indicated that probability of invasion was correlated with six climatic variables, including annual precipitation, annual mean temperature, max temperature of warmest month, mean diurnal range, temperature annual range, and isothermality. The states projected to be most at risk to invasion under the historical climate were Kentucky, Arkansas, Tennessee, North Carolina, Mississippi, Alabama, Georgia, and South Carolina. Future projections imply a northward shift of predominant species presence, with the most likely affected states being Kentucky, Virginia, Tennessee, North Carolina, Alabama, and Georgia. Our model provides important insights into the management of Japanese honeysuckle in the southern forestlands of the U.S. By identifying current and potential future high-risk and low-risk areas, our results can aid forest managers in developing long term monitoring and control strategies for effectively slowing Japanese honeysuckle range expansion and mitigating its effects.

The release of ornamental pets and associated pathogens outside their native range might directly or indirectly impact the recipient community. In temperate regions, e.g., central Europe, feral freshwater species of tropical and sub-tropical origins are mainly constrained to thermally polluted waters and thermal springs. However, species with high environmental plasticity and reproduction rates, such as the shrimp Neocaridina davidi, may adapt to colder water regimes over time. A widening thermal niche may eventually overcome thermal barriers, further expanding the range and enhancing transmission opportunities for host generalist parasites. This study assesses the observed (field observations) and theoretical (species distribution models) range expansion of N. davidi and associated parasites in Europe. We report three newly established N. davidi populations from thermally polluted waters in central Europe (Germany, Hungary, and Slovakia) and provide further evidence of its range expansion into colder environments. Species distribution models predict thermally suitable habitats in the Mediterranean and a foreseeable expansion into Western Europe and the Balkans by 2050. We confirm the presence of the microsporidian parasite Ecytonucleospora hepatopenaei in feral N. davidi populations across Europe and expand the list of microsporidians found in this host from two to four. Furthermore, we provide the first evidence of parasite spillover from/to the invasive crayfish Procambarus clarkii, suggesting that parasite exchange with native biota might be possible. Such possibility, coupled with an ongoing range expansion of N. davidi bolstered by human-mediated introductions and climate change, will likely exacerbate the impact on native biota.

It is often speculated that non-native invasive species undergo rapid changes in their phenotypic properties (i.e., traits) that provide adaptive advantage in their new environment. However, few studies have directly compared traits of invasive non-native species with their native counterparts to reveal whether such phenotypic changes occur, and which stages of initial introduction and subsequent invasion contribute to these shifts. We studied trait variation of an invasive tree, Pinus contorta, which is native to northwestern North America and invasive in the Patagonia region of South America (i.e., Argentina and Chile). Commercial plantations of P. contorta were introduced extensively in Patagonia from the 1970s onward, from an unknown seed origin within the Pacific Northwest, USA, where three sub-species are found, including subsp. contorta, latifolia, and murrayana. We employed a home-versus-away study approach, where we compared mean growth, defense, and reproduction trait values, and mean within-stand trait variation (Coefficient of Variation, CV) of Patagonia plantations, with the three native sub-species. We further compared mean traits, and trait CVs between invasive P. contorta and the Patagonia plantations from which they escaped. Patagonia plantations shared the most similar mean trait values with subsp. latifolia and murrayana, suggesting possible source populations. However, both mean trait values and trait CVs of Patagonia plantations differed from all three native sub-species, indicating potential founder effects, population bottlenecks, and/or plastic responses to their new environment that occurred during or after introduction. We also found evidence for selective change during invasion; however, these differences did not suggest growth traits were prioritized over defense traits, which was inconsistent with hypotheses that invaders exhibit an evolutionary trade-off between defense traits and growth traits. Our study highlights that processes occurring both at first introduction and establishment, as well as the subsequent invasion phase can influence the phenotype of successful invaders.

Many invasive fish conduct seasonal migrations, which create opportunities for large-scale removal. However, labor costs, cumbersome logistics, and environmental conditions (water depth, current, etc.) often make such efforts not feasible. We tested a semi-autonomous system for removing invasive common carp during spawning migrations in a natural stream (20 m wide, 1.5 m deep) over two migration seasons. A low-voltage, vertical deterrence and guidance system (DGS) was used to block the migrating carp and direct them into a large enclosure near shore. Additional electrodes placed in the enclosure created a sweeping electric field to push the carp towards one end and aggregate them over partially submerged conveyors that removed the carp from the water. Passive integrated transponder (PIT) tags and antennas were used to monitor carp behavior and removal efficacy. Each year, spawning migration lasted approximately two months and removal efforts occurred on 19 (year 1) and 21 (year 2) days. The DGS blocked over 90% of the carp and directed them into our trap. In year 1, 56% of the migrating carp were removed, and 68% were removed in year 2 (23,500 carp removed overall). In the final iteration of the system, a crew of three was able to conduct the removal, primarily by operating control systems on shore. Similar systems could be used for other invasive fish in larger and deeper environments where direct human labor is problematic. Such systems could also be used for native species to help them navigate passageways or to deflect them from entrainment areas.